Monocyte/macrophages are critical immune cells in many skin diseases. They are bone marrow-derived leukocytes that leave the bloodstream, enter skin, and differentiate into tissue monocyte/macrophages. There they can present antigen and produce cytokines or differentiate toward phagocytes. They are prominent around cutaneous tumors (melanomas, sarcomas, and carcinomas), and appear in skin in large numbers after ultraviolet (UV) light exposure. We propose to develop a technique for site-specific immunotherapy using genetically altered monocytes that would naturally home to inflamed skin. TGFbeta1 plays a major role in cutaneous repair and fibrosis by promoting collagen synthesis We hypothesize that we can target transduced monocytes expressing murine TGFbeta1 to skin of mice using UV light to provide site-specific immune therapy, ultimately for wound healing. BALB/c bone marrow cells will be transduced by a replication deficient retrovirus carrying TGFbeta1 and then differentiated in vitro to monocyte/macrophages. These pilot studies will allow us to develop the in vitro methodology in preparation for in vivo studies in wound healing. Aim I: Can retrovirally transduced bone marrow cells be driven toward monocyte/macrophage differentiation in vitro and selectively targeted in vivo to the skin of normal mice with UV light? Aim II. What are the optimal conditions for in vitro and in vivo expression of TGFbeta1 in monocyte/macrophages transduced with a TGFbeta1-GFP-containing retroviral vector? Significance. The retroviral cassette can be potentially be loaded with any gene of interest (cytokine, chemokine, growth factor or other immunomodulatory protein), thereby targeting genetically altered monocyte/macrophages to specific cutaneous sites in a variety of severe refractory inflammatory skin diseases (psoriasis and scleroderma) and cutaneous tumors (melanoma, sarcomas, and carcinomas).